Many types of input devices are available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens, and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens generally allow a user to perform various functions by touching (e.g., physical contact or near-field proximity) the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
However, the performance from a touch device can be compromised or degraded if the user is poorly grounded or if floating objects such as water drops make contact with the touch screen. For instance, a touch screen may not be able to discriminate between a touch input event from a poorly grounded user or object and a water drop making contact with the surface of the touch screen. This can degrade performance of the touch sensor panel since the device would want to recognize touch events from a poorly grounded user while at the same time ignore touch events generated by water drops on the touch screen.